Once again, with dispiriting regularity, yet another bill to make it easier to fight for equal pay for women and men has come up for debate by Congress. And once again, we are being bombarded by misleading punditry funded by interested thinktanks.

Is this issue dead, as claimed – and if so, is one of the key justifications for arguing that feminism is unnecessary, correct? Sadly, the answer is a resounding "no".

Opponents of the Paycheck Fairness Act have been stealthy and effective at seeding the debate with disinformation. A well-worn iteration on television and in highbrow analysis magazines is that the wage gap is really due to a "choices gap" – meaning that, these days, any wage disparity between men and women has to do only with the different lifestyle choices women are making. They say women opt for a "mommy track", for instance, or for professions that yield them more freedom to stay home with children.

The National Women's Law Center (NWLC) has been taking aim at these canards for many years now, arguing that the wage gap "isn't merely a matter of choice in occupation", for women are "typically paid less than men in the same occupation", regardless of pay level.

The truth is that a full-time working woman is paid an average of 77 cents for each dollar earned by a white male in the United States. The situation is even worse for African-American and Hispanic women, who earn 62 and 54 cents respectively for every white male dollar.

According to a factsheet (pdf) put together by the NWLC, the yearly gap between white women and men comes to a total of $10,784, and the trend is for this volume to grow over the years, especially for college graduates. Stresses the organization:

"Even when women make the same career choices as men and work the same hours, they earn less."

And, as women get older, the wage gap based on gender only increases. This may help explain why so many young women think this is not such a big deal, while older women will not wake up to the full extent of the systematic unfairness until it is too late for much organized action.

Who would be against fairness in pay for the same job, or against a bill to strengthen the hand of women when they seek to document and challenge demonstrable sex discrimination?

The powerful chambers of commerce in America, that's who. This homely-sounding title, "chamber of commerce", which sounds so very "main street", is really an euphemism for aggregated corporate interests – including global corporate interests. A paycheck fairness bill passed the House of Representatives in January 2009, but was rejected by the Senate in November 2010. Why would the Senate not push this right through? Because an unspoken driver of profits for corporate America is … the ability to pay women less, with impunity.

Women are the majority of the population, and are soon to be half of its workers. If that wage gap, which remains steady at about 23%, is forced shut, then corporations are looking at a 12% hike in total costs for labor – and a corresponding slice into their profits.

This equation was made very clear to me early in life, when a workers' union at Yale – Local 34, a union of food workers that was mostly female – went on strike. They made the case that the pay for their gender was way below the norm for men. But Yale's leadership explained to students, in effect, that the university would not negotiate with strikers. The reason was quite simple: if women were paid more equitably, Yale would lose significant profits that currently went to cover other costs. Their argument was that Yale couldn't profitably afford to close the gender gap: the bank balance needed the profits that lay right in that gender gap. These same "savings" for businesses and corporations are easy to identify across the country and, indeed, state by state – as long as women are poorly armed in fighting for equal pay rights.

What is behind this struggle, in addition to corporations' resistance to slashing unjustly aggregated profits derived from systematic unfairness?

Party politics is the answer: even before the Senate vote, the Washington Post asserted that the bill would not pass. This result, reflected the Post, has a strategic benefit for the president's team: Democrats will use this failure to make Republicans look as if they could not care less about gender fairness.

Obama's team, too, is calculating that a short-term hit on the corporate side will be balanced by maximizing the gender gap in November – a gap that has long skewed towards the Democrats, but which has been shrinking in the latest polls. Obama, thus, is creating gender-friendly "optics" – including a surprise appearance on a conference call about pay equity that, handily, included reporters. With this handy media audience, the president made his case:

"I don't have to tell you how much this matters to families across the country: if Congress doesn't act, then women are still going to have difficulty enforcing and pressing for this basic principle."

Rachel Maddow recently asked Mitt Romney's campaign what the Republican candidate's position was on the Pay Equity Act – and got a model of DC obfuscation. The short response assured that Romney "supports pay equity" – which is far from being a firm commitment. This was watered down further when argued that "as president, Mitt Romney will create a pro-jobs business climate that will put all Americans back to work." But working for how much, and under what conditions of unfairness?

On Tuesday, predictably, Senate Republicans blocked the bill. As long as Obama does not have to deliver on an actual law to insist on actual fairness in paycheck equity, he looks good in having "fought for women" without having had to deliver anything of real value to them that would cost him business backers.

So, for some, a loss really is a win – that is, Obama, who does not have to burn up any really important political capital with Wall Street, whose profit margins depend on keeping working women's worth artificially low. Meanwhile, women carry on losing out.